Compared to other types of display devices (eg, liquid crystal display units), OLED display devices have been studied broadly and are used preliminarily as next-generation displays because of their advantages of light weight, low power consumption, high contrast and high color gamut. Another advantage of OLED display devices is that they do not require backlighting, as compared to liquid crystal display devices.
One drawback of OLED display devices, however, is their sensitivity to air and humidity. Most organic substances in the OLED light emitting layer are sensitive to pollutants, O2 and water vapor in the atmosphere, and will directly cause problems such as deterioration of organic light emitting materials, low light emitting efficiency, abnormal light emission or being unable to emit light, etc., and meanwhile cause oxidation and corrosion of metal electrodes, so the packaging technology directly affects the stability and life of the OLED display device.
Active-matrix organic light emitting diodes (AMOLEDs) are more energy-efficient than passive-matrix organic light emitting diodes (PMOLED). Active-matrix light emitting diode has a good market prospect, but its packaging technology is also the key technology of AMOLED display products, and currently many display panel manufacturers are developing the film encapsulation (TFE) technology. TFE structure is generally a multi-layer film stack structure with two or more layers, which are divided into two types according to the function, inorganic water blocking layer and organic planarization planarization layer. FIGS. 1A and 1B are typical three-layer, five-layer film stack TFE structures.